After an even more devastating gas attack in 2013, Trump urgently advised President Barack Obama not to take military action against Assad in response. In numerous tweets, he warned of disastrous consequences and maintained there was nothing for the U.S. to gain from an attack on Syria. At the same time, he was critical of Obama for not enforcing his self-imposed “red line” when Assad crossed it and for publicly telegraphing the action he was considering taking.

Presidential candidate Donald Trump made many of the same points on the campaign trail in 2015 and 2016 as part of his “America First” message. He claimed his opponent, former Secretary of State Hillary Clinton, would start “World War III” by taking action in Syria.

After Tuesday’s attack, which left more than 70 people dead with horrifying images of child victims broadcast across social media and cable news, Trump suggested his perspective on Assad had changed, ominously suggesting that “something” needed to happen in response.

“Making sure Assad knows that when he commits such despicable atrocities he will pay a price is the right thing to do,” Senate Minority Leader Chuck Schumer, D-N.Y., said in a statement, adding that Trump must now consult with Congress as he develops a strategy for Syria.

Among those deeply displeased with President Trump’s decision, however, were some of candidate Trump’s most vocal fans.

Mike Cernovich, an alt-right figure who Trump’s son recently said deserved a Pulitzer Prize, spent 12 hours streaming outrage and distress over the strike from himself and his fellow Trump supporters. Since Tuesday, he had been spreading the theory that Assad was not responsible for the gas attack but it was instead committed by ISIS or “deep state agents.”

“Trump's base of support is gone if he goes to war with Syria, the same people who betrayed before election will betray him again,” he tweeted.

Author Ann Coulter seemed to be one of the hardest hit. “He told us he would be the president of America, not ‘the world.’ Could somebody show him pictures of Americans raped & killed by illegals?” she wrote.

Alex Jones of InfoWars, a conspiracy theorist whose reputation Trump once called “amazing,” insisted the gas attack was fake but he put a more positive spin on the missile strike. In a Facebook video Friday, he speculated the limited action was part of a plan to reconcile with Russia to form a coalition against ISIS in defiance of warmongers within the administration.

"Quite frankly, it's a win-win-win-win-win on so many fronts," he insisted.

Not all Trump supporters were disgusted. America First Policies, a non-profit established by former campaign aides, trumpeted the strike as showing the world that “America is no longer leading from behind.”

Whether the military strike represents a reversal of Trump’s “America First” doctrine is partly a matter of perspective.

Gordon Adams, a professor at American University and former White House official for foreign policy budgeting, said it was a stretch for Trump to claim in his statement Thursday that this strike was in the “vital national security interest of the United States.”

“It’s inconsistent with anything we know about Donald Trump,” he said, observing that Trump does not have a record of advocating for arms control and it does not appear that the administration has been heavily engaged in the effort to reach a diplomatic or military solution in Syria.

Many of the State Department and Defense Department jobs that would be involved in such efforts are not even staffed yet, so Adams struggled to understand Trump’s rationale for the strike.

“This has got to be some combination of toughness and impulse control,” he said. “It’s unhinged from anything strategic.”

Blaise Misztal, director of the national security program at the Bipartisan Policy Center, said a case could be made that Assad’s use of chemical weapons is a threat to U.S. troops in the region, though Trump has not yet convincingly made it.

“I think he owes it to the American people to give a much more full-throated defense of why it was in our national interest,” Misztal said.

If Assad has these weapons and is willing to use them, it is not far-fetched to believe he could give them to Hezbollah or they could end up in the hands of ISIS. Further instability in the Middle East is also bad for the U.S. and its allies, even if that position may be a hard sell with some voters.

“I think it’s a little bit of a complicated task because probably the average American may not feel that a chemical attack in Syria is a threat to their lives,” said Republican strategist Matt Mackowiak, host of the "Mack on Politics" podcast.

“This wasn’t just about responding to Syria,” he said. “It was about a new president showing he’s not going to be passive.”

In his 2013 tweets, Trump declared there was “no upside and tremendous downside” for the U.S. in attacking Syria. He was not wrong about the potential downsides, but it is now his responsibility to avert them and it is not yet clear he is prepared to do so.

“Is there a round two?” Adams asked. If there is a coordinated plan that entails further diplomacy or deeper military engagement, there is no indication of that yet.

One challenge in assessing Trump’s decision to strike is the mixed messaging from the administration. Last week, officials said removing Assad from power was not a priority, but Secretary of State Rex Tillerson said Wednesday he needs to go.

“Was this strike simply punishment for the chemical weapons use... or has he reevaluated his stance on Assad staying in power and is now going to take actions to ensure Assad is removed from power?” Misztal said.

Ambassador to the United Nations Nikki Haley said Friday that the U.S. is “prepared to do more” against Syria, but the White House has not said definitively if Trump wants Assad out of power.

According to Misztal, the White House must decide if the goal is a united Syria without Assad or breaking the country up into separate regions with the dictator possibly remaining in control somewhere.

“If you’re going to try to put Syria back together…there’s no way that you’re going to have any sort of stable Syria with Assad still there,” he said.

It is not unusual for a politician to shift positions from the campaign trail to the presidency. Mackowiak pointed somethout the difference between reading about a war crime as a Manhattan real estate developer and being briefed about it as commander-in-chief.

“I think all presidents have views when they run that are assaulted by reality when they’re sitting at the resolute desk in the Oval Office,” he said.

However, Adams maintained that this was not the same as, for example, President Obama routinely talking tough about China while campaigning and avoiding conflict with them as president.

“This is not, ‘Oh, another president changed his mind,’” he said. “This is not normal, because it can’t be explained by realism.”

Without a clear link to U.S. security or some sense that the president has an endgame in mind, according to Adams, this winds up looking like “toughness for its own sake.”

“What usually happens in the White House is you’re confronted with reality and you revise your strategy,” he said. “The problem here is there’s both inconsistency and the absence of strategy.”

While Trump has often said he wants to be unpredictable in foreign policy, Adams warned that this kind of inconsistency can unnerve allies and upset diplomatic relationship.

“There’s no question in my mind if this continues over the long term…it will accelerate the decline of American power,” he said. “It won’t enhance it, because people are going to find the United States just unpredictable and unreliable.”

Mackowiak expects Trump’s apparent about-face on Syria will have less impact domestically, even if some of his most high-profile alt-right acolytes felt betrayed on Thursday night. This is especially true if it does not lead to further military engagement.

“I just think the focus will return to the other issues…I don’t see there being a lot of lasting anger there,” he said. As Trump advances his agenda on health care, taxes, and other matters that impact his base more directly, the disappointment may fade.

He also noted that the Syria strike provides an opportunity to win over some of Trump’s establishment opponents in both parties, at least for the moment.

“Politics is about addition, not about subtraction and division… The question is can he build on it,” he said.

Philip Klein of the Washington Examiner argued in an op-ed Friday that many Trump voters will not see his military action as the contradiction some in the media do.

“They were the type of people who cheered on ‘shock and awe’ during the initial Iraq invasion, but didn't like the idea of America spilling blood and treasure forever to keep Arabs from killing each other,” he wrote.

Time will tell whether Thursday heralds a new era of Middle East military entanglement, but Mackowiak said it does demonstrate that, for better or worse, President Trump will not be beholden to the social media musings and campaign rhetoric of citizen Trump.

“I don’t think he sits around thinking, ‘Here’s the right decision, but I can’t do that because of a tweet from 4 years ago.’”